1. Field of the Invention
The invention broadly relates to the field of sectional utility poles, and more particularly relates to the field of inter-connections for securing the sections of such poles.
2. Description of the Related Art
Multi-sectional utility poles are used for a variety of purposes such as highway luminaire supports and utility poles, e.g., telephone, cable and electrical. Poles of a given length are often designed in multiple sections to provide for an increased ease of transporting by truck, railroad, or even cargo plane. The length may also be restricted due to other field requirements. All such multi-section poles, however, must address the issues of joining each of the sections of pole to one another and appropriately securing the joints in the field during installation.
One common method of making multi-section poles is to use tubular sections which are uniformly tapered along their entire length such that the top is narrower than the bottom. These uniformly tapered sections are then secured to each other by sliding one section over another. The tapered sections are designed so that the bottom portion of a top section slides over the top portion of a bottom section. The portions of the two sections that are in contact, ideally, form a tight fit. There are several limitations associated with this technique.
Poles of this type are typically expensive to fabricate. Additionally, when assembling a pole vertically, it is necessary to suspend the upper sections one by one from a helicopter or crane or other device, which is expensive in terms of the equipment needed and in terms of the labor involved. Such an assembly process can also take a great deal of time. Further, the uniformly tapered sections can also be expensive to produce.
Another factor which can contribute to the cost and the time involved in assembly is a lack of fungibility between the sections. Insofar as the individual sections of a complete pole are designed to be used together for that specific pole, this requires additional sorting at the jobsite and can cause delays if the sections are not delivered in the proper order for assembly.
Accordingly, there is a need for a multi-sectional utility pole and a method of fabricating it which overcome these limitations.